Why do some genera have so many species?

Probably because Rana is a well-established name for all North American true frogs (some are still retained in Rana, others now in Lithobates) and there is no clear definition of where you draw the line for separating genera.

Added: As long as the arrangement isn’t paraphyletic, you can have a huge genus encompassing many species (perhaps with 2 or more subgenera) or a bunch of smaller genera containing fewer species.


As I know there were no major problems in dividing European green frogs to this separate genus, interesting how people see it, but it defenitely is a lesser problem comparing to renaming Drosophila, when I used a key for them it had all those new groups in it already as separate genera even though key was for Drosophila, so it’s a kinda good concept on how it should be treated for now.

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I’d appreciate the elevation of the different subgenera to genus level.
iNat lacks the taxon levels necessary to specify taxa below subgenus and the situation with Drosophila is the main reason why I support this feature request: There are some cosmopolitan species, quite often observed, easy to narrow down to 2-3 related species belonging to one species group, but as this taxon is not available, when IDing these observations I have to select the next-higher category which comprises >1,000 species

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I would argue that the ICZN, rather than iNat, lacks the taxon levels necessary. The botanical ranks Section and Subsection are recognized in the iNat taxonomy because they are part of the ICN (although I acknowledge iNat does not include (Sub)Series), whereas comparable ranks don’t exist under the ICZN. “Species group” is not a formal taxonomic rank.


That’s really interesting, and its funny that the stink is being made over having to change D. melanogaster and not the huge diversity of Hawaiian Drosophilids, It reminds me a lot of happened with Acacia s.l. where the Australians refused to accept taxonomic rules and continued on until the rest of the world conceded. I guess I don’t understand the big deal with changing names if the research warrants it. Racosperma isn’t that bad :rofl:


I wonder if there is a very small chance that different mothers could give birth to children with identical genomes? An even smaller chance that a chimpanzee could give birth to an offspring with a human genome? A giraffe?

infinitesimally small

probably the fetus would not be viable and would be aborted in that case

History proves chance is reaaaaaly small, like one in multi quadrillion or less, cause maturations are random and you need them to be done in many genes and be extremely precise and of different kind (duplicating, changing place of part of gene, etc.), so this chance is a thing for theoretical talk, but in practice it doesn’t happen, maybe from the view of a genetic expert it can be called impossible. Plus we have to consider our mitochondrial DNA should change too and some other types of non-main DNA that take part in making the species what it is. And it’s not totally clear what non-genome DNA does other than helping with viruses, it can matter a lot and another species simply can lack some viral genes in it or some non-working ancestral gene.

I would think not by chance, maybe in the lab.

Twin mothers in a cloning situation?

Last summer I took some photos of moths at night in the Grand Canyon. They were all in exactly the same environment, resting on rocks on the ground. They were just about the same size, and the same, triangle shape, as well. The main difference between them, seemed to be the color patterns of the wings. Yet, two of them are from different genuses, maybe even different families. I find that remarkable. A third one still hasn’t been identified beyond Lepidoptera


Hey all, the conversation is wandering off-course. If you want to start a new conversation, please start a new thread. I can move your previous posts there if you like.

They’re completely different moths, totally, with different pattern, different wings, different genitalia. So they don’t fall under the theme of this topic.

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Two words: Oncorhynchus mykiss.

Now that we have cleared that all up, I am off to pick some dandelions… At least, I think they’re dandelions.

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A species is a group of organisms that breed with each other and don’t breed with organisms of other groups. That’s the biological species concept. It’s our “gold standard” for what a species should be. There are complications.

What if the populations are geographically separated so they don’t interbreed, but they might interbreed if they met? What if these populations are identical? Similar? Clearly different?

What if the populations sometimes breed together but usually don’t? How much breeding together is required before we consider them one species?

What if the species are asexual?

What if (the hardest of all to deal with) they’re usually asexual, forming huge clones, but sometimes they have sex and produce offspring that establish new clones?

Making taxonomic decisions can be hard.


And to answer your other question, no there’s no certain amount of genetic differentiation that causes us to consider two populations the same or different species. Sometimes a small but important genetic difference makes interbreeding impossible? Other times, what is clearly one interbreeding population includes much variation.


Which is why I am skeptical of some of the new species descriptions based mainly on genetic analysis.


Suppose you have numerous populations spread out along some geographical or ecological gradient. Are there any examples where they will breed with the population closest to them but not with the more distant ones? So population D will breed with C and E but not A, B, F, etc. B will breed with A and C but not D, E etc. In such a case, where would you draw the line between species? I think herring gull / lesser black backed gull Larus argentatus / fuscus might be an example of this situation.


Is it a standart now, when we know bout so many hybrids? We were taught in univercity it’s now can’t be a single reason to divide species.


There are several examples proposed as “ring species,” the ones where each unit can breed with the adjacent populations but the ones at the ends of the ring meet and can’t interbreed. These examples, including the gulls you mention, are controversial. In all cases examined very closely so far, there are breaks in the ring – places where the adjacent populations don’t actually interbreed. So although ring species are theoretically possible, they may not actually exist.